FIG. 1A illustrates an example schematic (100) for an analog temperature sensor system. The analog temperature sensor system includes two resistors (R1, R2), a zener regulator (ZREG), and an optional gain block (G).
Zener regulator ZREG is connected between a first terminal and a ground terminal, and provides a control signal (ADJ) output. Resistor R1 is connected between power supply terminal VDD and the first terminal. Resistor R2 is connected between the first terminal and a ground terminal, and has a variable resistance value that is adjusted by control signal ADJ. The gain block receives a sense voltage (VSNS) from the first terminal and provides an output voltage (VOUT) at a second terminal.
FIG. 1B illustrates the operational sense voltage (VSNS) for the analog temperature sensor system that is illustrated by FIG. 1A. The sense voltage (VSNS) has a nominal value that is defined at a predetermined operating temperature. The sense voltage (VSNS) varies from the nominal value over a defined temperature range. As illustrated by FIG. 1B, the sense voltage (VSNS) has a predetermined slope over operating temperatures T1 through T2 that corresponds to 10 mV/° K. In another example, the sense voltage may have a slope that corresponds to 10 mV/° C. The gain block (G) may be employed to provide an output voltage (VOUT) that corresponds to a gain scaled version of the sense voltage (VSNS). The voltages resulting from the operation of the analog temperature sensor system (VSNS and VOUT) are proportional to absolute temperature (VPTAT).